This invention was made with Government support under Contract No. N0014-86-K-0694 awarded by the Office of Naval Research.
This invention relates generally to superconducting thin films and, more particularly, to a method for patterning a thin film of superconducting material.
Since the discovery of high Tc superconductors, there has been increasing interest in the development of techniques for patterning thin film superconducting materials, particularly YBaCuO, for device fabrication. This is evidenced by the published papers listed in Information Disclosure Statement submitted by applicants, the disclosures of which are hereby incorporated herein by reference, which describe techniques for fabrication of thin films of high transition temperature superconducting materials and methods for patterning such films. The patterning methods most commonly used heretofore have utilized both wet and dry processes. The known wet processes include lift-off, ion or electron beam irradiation, chemical etching, and laser direct-writing, all of which involve removal of material using chemical solutions, which, because the superconductor material is sensitive to water and chemicals, may possibly damage the superconductor surfaces. The known dry processes of laser ablation or laser-reactive patterning are limited by the area of the localized laser beam.
Accordingly, it is an object of the present invention to provide an improved method for patterning thin film superconducting materials. Another object of the invention is to provide a method for forming a patterned superconducting oxide film on a substrate using a combination of well-developed semiconductor patterning techniques and laser direct-write etching. A further object of the invention is to provide a simple, chemical free, and relatively rapid method of patterning high T.sub.c superconducting films. Yet another object of the invention is to provide a method for patterning superconducting films that can be combined with known processing technology for manufacturing superconducting interconnects, electrodes of semiconductor devices, and Josephson junction type structures or superconductor quantum interference devices (SQUID).